APA (7th ed.) Citation

Milne, A. A. (1999). The Red House Mystery. Project Gutenberg.

Chicago Style (17th ed.) Citation

Milne, A. A. The Red House Mystery. Project Gutenberg, 1999.

MLA (9th ed.) Citation

Milne, A. A. The Red House Mystery. Project Gutenberg, 1999.

Warning: These citations may not always be 100% accurate.